A variety of tools have been known and used in the past for the purpose of scarifying or breaking up a surface, an example of which is illustrated in my earlier U.S. Pat. No. 4,502,223. Such tools have been found to be particularly effective when the cutting or breaking elements are arranged to impart a sideways force across the surface and across the direction of travel of the tool.
A disadvantage hitherto associated with such an arrangement, however, has been that although the tool is moved back and forth across the surface in a scrubbing type of motion, it only cuts into the surface while moving in one direction, and has little or no effect on the surface on the return stroke. It has also been found difficult to provide a simple and effective means for precisely limiting the depth of penetration of the cutters on a surface such as wallpaper, particularly on uneven surfaces such as embossed or textured wallpaper.